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CHARACTERIZATION OF WATER TABLES IN OREGON SOILS WITH REFERENCE TO TRAFFICABILITY

THREE NEAR-MODAL TEST SITES WERE ESTABLISHED ON EACH OF THE FIVE SOIL SERIES (WILLAMETTE, WOODBURN, AMITY, CONCORD, AND DAYTON) OF THE WILLAMETTE DRAINAGE SEQUENCE IN WESTERN OREGON. FIELD AND LABORATORY TESTS ON SOILS FROM THE 15 TEST SITES WERE INITIATED IN THE FALL OF 1963 AND TERMINATED IN THE SUMMER OF 1965. THE OBJECTIVES OF THE STUDY WERE TO (1) DETERMINE WHETHER PARTICULAR WATER TABLE REGIMES ARE ASSOCIATED WITH SPECIFIC SOIL TYPES, (2) ACHIEVE THE CAPABILITY FOR APPRAISING WATER TABLE REGIMES FROM SOIL MORPHOLOGICAL INFORMATION, AND (3) GAIN BACKGROUND KNOWLEDGE NEEDED IN THE DEVELOPMENT OF PREDICTION METHODS FOR WATER TABLE DEPTHS, SOIL MOISTURE CONTENTS, AND SOIL STRENGTHS. DATA OBTAINED DAILY AT EACH SITE INCLUDED MAXIMUM AND MINIMUM AIR TEMPERATUES, PRECIPITATION, GROUNDWATER DEPTHS, AND ELECTRICAL RESISTANCE MEASUREMENTS OF SOIL MOISTURE CONTENT AND TEMPERATURE. DATA OBTAINED PERIODICALLY INCLUDED GRAVIMETRIC SOIL MOISTURE CONTENTS, SOIL STRENGTHS, AND THE STATE OF THE GROUND AND VEGETATION. DATA COLLECTED AT OPPORTUNE TIMES DURING THE COURSE OF THE STUDY INCLUDED ATTERBERG LIMITS, GRAIN-SIZE DISTRIBUTIONS, SPECIFIC GRAVITIES, ORGANIC MATTER CONTENTS, MOISTURE CONTENTS SPECIFIED TENSIONS, DRY DENSITIES, SITE DESCRIPTIONS, AND SOIL PROFILE DESCRIPTIONS. THESE DATA HAVE BEEN CONDENSED IN TABULAR AND GRAPHIC FORM FOR PRESENTATION HEREIN. ALSO INCLUDED ARE BRIEF DESCRIPTIONS OF THE GEOLOGY, TOPOGRAPHY, PHYSIOGRAPHY, CLIMATE, SOILS, AND LAND USE OF THE STUDY AREA. CORRECTED SOIL MOISTURE UNIT READINGS AND CORRESPONDING GRAVIMETRIC SOIL MOISTURE MEASUREMENTS ARE INCLUDED IN APPENDIX A. ANALYSIS OF THE DATA IS PRESENTED IN VOLUME II OF THIS REPORT. /AUTHOR/